      SUBROUTINE ZERO_S(A,LEN)
C
C ZEROS OUT THE FIRST LEN ELEMENTS OF DOUBLE PRECISION VECTOR A.
C
CEND
      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
      REAL*4 A(LEN)
C
      CALL SSCAL(LEN, 0.0, A, 1)
C     M=MOD(LEN,5)
C     IF(M.NE.0) THEN
C      DO 1 I=1,M
C       A(I)=0.D0
C      CONTINUE
C     ENDIF
C     IF(LEN.GE.5) THEN
C      MP1=M+1
C      DO 3 I=MP1,LEN,5
C       A(I)=0.D0
C       A(I+1)=0.D0
C       A(I+2)=0.D0
C       A(I+3)=0.D0
C       A(I+4)=0.D0
C      CONTINUE
C     ENDIF
C      DO 10 I=1,LEN
C       A(I)=0.D0
C10    CONTINUE
      RETURN
      END
